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Experimental study on the compression-shear performance of a new-type circumferential joint of shield tunnel

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Underground Space 2024年第1期14卷 138-155页

作者： Ziyang Zhou Kun Feng Yiteng Liu Bohan Wu Chunfang Lu Gang Lin Chuan He Key Laboratory of Transportation tunnel Engineering of Ministry of Education Southwest Jiaotong UniversityChengdu 610031China China Academy of Railway Sciences Corporation Limited Beijing 100081China China Railway Eryuan Engineering Group Co. Ltd.Chengdu 610031China

To investigate the compression-shear behavior of a new circumferential joint based on the sleeve-straight bolt combination type connection of large-diameter shield tunnels,a series of full-scale joint experiments was carried *** the process of the experiment,more attention was paid to the specimen displacement,bolt stress and joint damage *** the basis of these experiment phenomena,this study discussed the compression-shear bearing process of the new connector,analyzed the damage mode of the joint structure,and finally evaluated the performance of the new *** is found that the bearing process of the joint can be divided into four stages:the transitional stage for overcoming the friction of the concrete,the sleeve bearing stage for the sleeve bearing shear loads alone,the combined bearing stage for bearing shear loads by the connector system,and the structural damage stage for structural instability and *** speaking,affected by connector position and hand hole,the positive compression-shear stiffness of the joint is less than the negative compression-shear stiffness,and the positive shear strength of the joint is greater than the negative shear *** increase of longitudinal axial force will improve the compression-shear performance of the *** relationship between longitudinal axial force and joint stiffness is a logarithmic *** use of new type of connector can effectively improve the compression-shear stiffness of joints under low shear loads,but the application of straight bolts will lose part of the strength performance.

关键词： shield tunnel New type of connector Shear resistance Full-scale experiment Circumferential joint

Numerical and experimental analyses of methane leakage in shield tunnel

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Frontiers of Structural and Civil Engineering 2023年第7期17卷 1011-1020页

作者： Jie HE Hehua ZHU Xiangyang WEI Rui JIN Yaji JIAO Mei YIN College of Civil Engineering Tongji UniversityShanghai 200092China State Key Laboratory for Disaster Reduction in Civil Engineering Tongji UniversityShanghai 200092China Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education Tongji UniversityShanghai 200092China d Department of Civil and Environmental EngineeringBrunel UniversityLondon UB83PHUK

tunnels constructed in gas-bearing strata are affected by the potential leakage of harmful gases,such as methane *** on the basic principles of computational fluid dynamics,a numerical analysis was performed to simulate the ventilation and diffusion of harmful gases in a shield tunnel,and the effect of ventilation airflow speed on the diffusion of harmful gases was *** the airflow speed increased from 1.8 to 5.4 m/s,the methane emission was diluted,and the methane accumulation was only observed in the area near the methane leakage *** influence of increased ventilation airflow velocity was dominant for the ventilation modes with two and four *** addition,laboratory tests on methane leakage through segment joints were *** results show that the leakage process can be divided into“rapid leakage”and“slight leakage”,depending on the leakage pressure and the state of joint *** on the numerical and experimental analysis results,a relationship between the safety level and the joint deformation is established,which can be used as guidelines for maintaining utility tunnels.

关键词： shield tunnel harmful gas leakage numerical analysis laboratory test

Mechanical behavior of segment rebar of shield tunnel in construction stage

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第7期9卷 888-899页

作者： Jun-sheng CHEN Hai-hong MO Department of Civil Engineering South China University of Technology Guang＇zhou 510640 China State Key Laboratory of Subtropical Building Science South China University of Technology Guang＇zhou 510640 China

In this paper, a 3D finite element （FE） program ADINA was applied to analyzing a tunnel with 9 segment tings. The loads acting on these segment tings included the squeezing action of tail brush of shield machine under attitude deflection, the jacking forces, the grouting pressure and the soil pressure. The analyses focused on the rebar stress in two statuses：（1） normal construction status without shield machine squeezing; （2） squeezing action induced by shield machine under attitude deflection. The analyses indicated that the rebar stress was evidently affected by the construction loads. In different construction status, the rebar stress ranges from -80 MPa to 50 MPa, and the rebar is in elastic status. Even some cracks appear on segments, the stress of segment rebar is still at a low level. It is helpful to incorporate a certain quantity of steel fiber to improve the anti-crack and shock resistance performance.

关键词： shield tunnel Construction Segment Rebar Finite element (FE) analysis

Research on the method of construction disturbance zoning for shield tunnel approaching to urban structures

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Frontiers of Structural and Civil Engineering 2024年第11期18卷 1663-1679页

作者： Ziyang ZHOU Fukang GUO Jianzhong NI Kun FENG Jingxuan ZHANG Yiwen LIU Key Laboratory of Transportation tunnel Engineering of Ministry of Education Southwest Jiaotong UniversityChengdu 610031China Hangzhou Fuyang City Construction Investment Group co. Ltd.Hangzhou 310000China

This paper presents a calculation method that evaluates the extent of disturbance based on structural safety ***,it summarizes the assessment methods for construction disturbance zones in shield tunneling near pile foundations,urban ground structures,and underground ***,taking the construction of the Chengdu Jinxiu tunnel under bridges and urban pipelines as the engineering background,a study on the disturbance zoning of adjacent structures was *** most intense disturbance occurs within one week of the tunnel underpass process,and it has a significant impact within a range of two times the tunnel diameter along the tunnel *** bridge pile and bridge deck experience less disturbance from tunnel approaching construction,with a maximum disturbance zone characterized as medium *** the other hand,underground pipelines are subjected to more significant disturbances from tunnel construction,with a maximum disturbance zone classified as strong *** implementation of“bridge pile sleeve valve pipe grouting&underground pipeline ground grouting&tunnel advance grouting”in the field effectively limits the vertical settlement of bridges and pipelines,resulting in a decrease of approximately 0.1 in disturbance level for the *** disturbance zoning method can assess tunnel disturbance with structures,identify high-risk interference locations,and facilitate targeted design reinforcement solutions.

关键词： shield tunnel approaching construction field monitoring disturbance zoning method

Study on the long-term performance of shield tunnel passing through the gas-bearing strata

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Underground Space 2023年第2期9卷 1-19页

作者： Jie He Xiangyang Wei Mei Yin College of Civil Engineering Tongji UniversityShanghai 200092China State Key Laboratory for Disaster Reduction in Civil Engineering Tongji UniversityShanghai 200092China Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education Tongji UniversityShanghai 200092China Civil and Environmental Engineering Department Brunel University LondonLondon UB83PHUK Recei

When the shield tunnel passes through the gas-bearing strata,gas and water leakage may occur depending on the sealing performance of the segment *** process involves the complex multiphase seepage flow phenomenon in unsaturated *** this study,a fully coupled solid-liquid-gas model of the GIL Utility tunnel was established to investigate the influence of the high-pressure gas on the mechanical properties of the tunnel segments and *** constitutive model of the Extended Barcelona Basic Model was imple-mented to simulate the effect of the seepage process on soil *** results show that significant upward displacement occurred in the gas reservoir and its overlying strata,and the maximum displacement reached 30 *** addition,during the leakage of the gas and the water,an increase in the average soil effective stress was *** would induce a reduction in the suction and expansion of the yield *** tunnel tended to be stable from 20 years onwards,thus the soil deformation due to the water leakage only occurred at the early *** addition,the joint opening under the most unfavorable internal force combination was 0.69 mm,and the correspond-ing bolt stress was 119.5 MPa,which is below the yield *** results of this study help to understand the influence of high-pressure gas on tunnel safety and the sealing performance of the joints.

关键词： A coupled solid-liquid-gas model Unsaturated soil Multiphase seepage Gas-bearing strata shield tunnel FEM

Piezoelectric sensing method for segmental joint contact stress during shield tunnel construction

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Underground Space 2024年第4期17卷 82-99页

作者： Guodong Jiang Minghao Dai Guozhu Zhang Limin Gao Institute of Geotechnical Engineering Southeast UniversityNanjing 211189China Nanjing Metro Group Co.Ltd Nanjing 210000China No.4 Construction Company of China Petroleum Pipeline Engineering Co.Ltd Langfang 065000China

The emergence of curved shield tunnels poses a significant construction *** the quality of the segment assembly is not guaranteed,many segment cracks and damage will result from the stress *** the contact stresses between segmental joints is necessary to improve the quality of segments assembled for shield tunnel *** difluoride(PVDF)piezoelectric material was chosen for the sensor because it can convert contact stresses into electrical signals,allowing the state of the segmental joints to be effectively *** matches the working environment between the segmental joints of the shield tunnel,where flexible structures such as rubber gaskets and force transfer pads are *** study proposes a piezoelectric sensing method for segmental joints in shield tunnels and conducts laboratory tests,numerical analyses,and field tests to validate the feasibility of the *** results indicate that the PVDF film sensor can effectively sense the entire compression process of the gasket with different amounts of *** piezoelectric cable sensor can effectively sense the joint offset direction of the *** differently shaped sections,the variation in the force sensed by the piezoelectric cable sensors was different,as verified by numerical *** the field test,it was found that the average contact stress between the segmental joints was in the range of 1.2–1.8 MPa during construction of the curved shield *** location of the segmental joints and the type of segment affect the contact stress *** field monitoring results show that piezoelectric sensing technology can be successfully applied during assembly of the segments for effective sensing of the contact stress.

关键词： shield tunnel Segmental joint Contact stress Piezoelectric sensor

Study on effect of segments erection tolerance and wedge-shaped segment on segment ring in shield tunnel

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第11期7卷 1864-1869页

作者： CHEN Jun-sheng MO Hai-hong Department of Civil Engineering South China University of Technology Guangzhou 510640 China

Deformation and dislocations of segments of shield tunnel in construction stage have apparent effect on tunnel structure stress and even cause local cracks and breakage in tunnel. 3D finite element method was used to analyze two segment ring models under uniform injected pressure: (1) segment ring without wedge-shaped segment, which has 16 types of preinstall erection tolerance; (2) segment ring with wedge-shaped segment, which has no preinstall erection tolerance. The analysis results indicate that different erection tolerances can cause irregular deformation in segment ring under uniform injected pressure, and that the tolerance values are enlarged further. Wedge-shaped segment apparently affects the overall deformation of segment ring without erection tolerances. The uniform injected pressure can cause deformation of ring with wedge-shaped segment irregular, and dislocations also appear in this situation. The stress of segment with erection tolerances is much larger than that of segment without erection tolerances. Enlarging the central angle of wedge-shaped segment can make the irregular deformation and dis- locations of segments smaller. The analysis results also provide basis for erection tolerance control and improvement of segment constitution.

关键词： shield tunnel Segment Erection tolerance 3D finite element analysis

Deformation-based longitudinal equivalent stiffness beam model for shield tunnel and its application in seismic deformation method

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Underground Space 2024年第4期17卷 280-299页

作者： Pingliang Chen Ping Geng Junbo Chen Qi Yang Key Laboratory of Transportation tunnel Engineering Ministry of EducationSouthwest Jiaotong UniversityChengdu 610031China State Key Laboratory of Intelligent Geotechnics and tunnelling Chengdu 610031China Technology Center of Sichuan Road&Bridge Group Co. LtdChengdu 610041China

In the longitudinal seismic deformation method for shield tunnels,one of the most commonly used is the longitudinal equivalent stiffness beam model(LES)for simulating the mechanical behavior of the *** this model,axial deformation and bending deformation are independent,so the equivalent stiffness is a constant ***,the actual situation is that axial deformation and bending deformation occur simultaneously,which is not considered in *** present,we are not clear about the effect on the calculation results when axial deformation and bending deformation occur ***,in this paper,we improve the traditional LES by taking the relative deformation as a load and considering the coordinated deformation of axial and bending degrees of *** improved model is called DNLES,and its neutral axis equations are an explicit ***,we propose an iterative algorithm to solve the calculation model of the DNLES-based longitudinal seismic deformation *** a calculation example,we find that the internal forces based on LES are notably underestimated than those of DNLES in the compression bending zone,while are overestimated in the tension bending *** considering the combined effect,the maximum bending moment reached 13.7 times that of the LES model,and the axial pressure and tension were about 1.14 and 0.96 times,*** analysis reveals the coordinated deformation process in the axial and bending directions of the shield tunnel,which leads to a consequent change in equivalent *** explains why,in the longitudinal seismic deformation method,the traditional LES may result in unreasonable calculation results.

关键词： shield tunnel Longitudinal seismic deformation method Longitudinal equivalent stiffness beam Combined axial and bending deformation

Deformation control criterion of shield tunnel under lateral relaxation of soft soil

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Frontiers of Structural and Civil Engineering 2023年第5期17卷 780-795页

作者： Shimin WANG Xiaoyu PENG Hang ZHOU Xuhu HE Anqi ZHOU Bing CHEN Key Laboratory of Transportation tunnel Engineering Ministry of EducationSouthwest Jiaotong UniversityChengdu 610036China Guangdong Provincial Railway Construction Investment Group Co. LtdGuangzhou 510080China

Metro shield tunnels under the lateral relaxation of soil(LRS)are susceptible to significant lateral deformations,which jeopardizes the structural safety and ***,deformation control standards for such situations have not been clearly ***,based on a specific case,a model test is conducted to realize the LRS of a shield tunnel in a sandy stratum to reveal its effect on segment ***,a deformation control criterion is *** LRS is simulated by linearly reducing the loads applied to the lateral sides of the segment *** lateral unloading,the lateral earth pressure coefficient on the segment decreases almost exponentially,and the structural deformation is characterized by horizontal expansion at the arch haunches and vertical shrinkage at the arch vault and arch *** on the mechanical pattern of the segment structure and the acoustic emission,the deformation response of a segment can be classified into three stages:elastic and quasi-elastic,damage,and rapid deformation *** a shield tunnel with a diameter of approximately 6 m and under the lateral relaxation of sandy soil,when the ellipticity of the segment is less than 2.71%,reinforcement measures are not ***,the segment deformation must be controlled when the ellipticity is 2.71%to 3.12%;in this regard,an ellipticity of 3%can be used as a benchmark in similar engineering projects.

关键词： shield tunnel lateral relaxation of soil deformation control criterion of segment structure model test